Solution applying method

ABSTRACT

In etching using an etching solution, irradiating ultraviolet light is irradiated into a resist patterned on an etching substrate or a film formed on the etching substrate and then an etching solution is applied to the etching substrate while rotating the etching substrate. Also, ozone water is applied in contact with the resist and then an etching solution is applied to the etching substrate while rotating the etching substrate. In crystallization using a metal element such as nickel for promoting crystallization of silicon, irradiating ultraviolet light is irradiated into a resist patterned on an substrate or a film formed on the substrate and then a nickel solution is applied to the substrate while rotating the substrate. Also, ozone water is applied in contact with the resist and then the nickel solution is applied to the substrate while rotating the substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solution applying apparatus and asolution applying method used for a technique for applying a solution,such as wet etching, in a forming technique for a semiconductor device.

2. Description of the Related Art

Processes for applying a solution to a substrate are often performedwhen manufacturing semiconductor devices such as thin film transistors(TFTs) in which thin films of semiconductor, insulator and metal or thelike are laminated and formed on a semiconductor substrate or glasssubstrate, such as semiconductor integrated circuits, active matrix typeliquid crystal electro-optical devices and the like.

Commonly used solution applying methods include (1) a method forimmersing (dipping) a substrate into a bath containing a solution inbatch etching method or the like, (2) a method for applying a solutionas a shower from a plurality of jets onto the upper surface of thesubstrate (a spray method), and (3) a method for applying a solutionfrom a nozzle near the center of the rotating surface while thesubstrate is rotated (spin coating method).

The spin coating method (3) is suitable for so-called single wafer typeprocessing with which it is possible to treat substrates uniformly, oneat a time. However, in the method (3), since the substrate is rotated at100 to 1000 rpm, a solution which is caused to drop or flow onto therotating surface near the center moves at high speed toward the outsideof the rotating surface. Therefore the moving speed of the solution onthe substrate is much higher than the methods (1) and (2). That is, themethod (3) has good solution circulation. Further, the moving speed ofthe solution at the peripheral portion of the rotating surface is higherthan at the center portion of the rotating surface because ofcentrifugal force.

Conventionally, the following problems occurs due to the above fact.When spin etching is performed using an etching solution which has alarge contact angle with respect to the resist, for example,hydrofluoric acid based etching solutions in a wet etching process, theetching solution does not adequately wet the surface to be etched, sothat the etching solution forms balls and flows off. As a result,island-shaped etching irregularities form over the entire surface of thesubstrate. In particular, when aluminum mixed acid based etchingsolution is used, a portion which is not etched remains at theperipheral portion.

Thus the phenomenon occurs that etching is performed nonuniformly withina single substrate surface. This phenomenon becomes more marked as thefineness of the resist pattern width progresses. That is, since anetching solution does not penetrate uniformly into the fine portion,solution circulation is liable to be unsatisfactory.

Further, the phenomenon becomes more marked as the area of the substrateincreases. In other words, if the area of the substrate increases,contact between the etching solution and the surface of the substrate isliable to be nonuniform. Also, irregularities also occur in the spraymethod (2).

In a liquid crystal display device, since several hundred thousand thinfilm transistors (TFTs) are formed on a single substrate such as quartzor glass in the same process, defect of one TFT causes defect of asubstrate. Therefore, irregularity of the above etching causes adecrease in yield.

Also, a technique for selectively crystallizing an amorphoussemiconductor material using a catalytic action of a metal element inproducing a TFT using a resist (mask) is disclosed by Japanese PatentPublished Application No. 6-319167. In the technique, a resist (mask) isformed on an amorphous silicon film, and then a solution containing ametal element such as nickel is added (applied). As a result, in anopening of a photoresist (mask), the metal element is selectively incontact with the surface of the amorphous silicon film. In this state,by heating with thermal annealing or laser light irradiation, theamorphous silicon film is crystallized from a region which the metalelement is in contact with.

However, if the solution containing a metal element is uniformly added,since an amorphous silicon film is not crystallized sufficiently,characteristics of elements on the same substrate are different fromeach other.

Conventionally, in order to uniformly add (apply) a solution containinga metal element, an extremely thin oxide film is formed on the surfaceof an amorphous silicon film, so that wetting degree of the amorphoussilicon film increases, or an interface active agent is added to thesolution. However, this increases the number of process steps necessaryto form the device.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above problems, andto provide a solution applying (adding) apparatus and method foruniformly applying a solution to a substrate on which a photoresist isformed, with good solution circulation, in a solution applying methodsuch as spin coating in which the solution moves on the substrate at ahigh speed and has good solution circulation.

An object of the present invention is to provide a solution applyingapparatus and method for uniformly applying a solution using a desiredsolution applying (dropping or flowing) method, in a solution applyingmethod such as spin etching in which an etching solution moves on anetching surface at a high speed and has good solution circulation.

In order to solve the above problems, one invention disclosed in thespecification is a solution applying apparatus having means for applyingan etching solution uniformly to an etching substrate on which apatterned resist is formed or a film formed on the etching substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for irradiating ultraviolet light to a resistpatterned on an etching substrate or a film formed on the etchingsubstrate and means for applying an etching solution to the etchingsubstrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for irradiating ultraviolet light to a resistpatterned on an etching substrate or a film formed on the etchingsubstrate, means for applying an etching solution to the etchingsubstrate, and means for rotating the etching substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for applying ozone water in contact with aresist patterned on an etching substrate or a film formed on the etchingsubstrate and means for applying an etching solution to the etchingsubstrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for applying ozone water in contact with aresist patterned on an etching substrate or a film formed on the etchingsubstrate, means for applying an etching solution to the etchingsubstrate, and means for rotating the etching substrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, irradiating ultraviolet light to a resistpatterned on an etching substrate or a film formed on the etchingsubstrate and then applying an etching solution to the etchingsubstrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, irradiating ultraviolet light to a resistpatterned on an etching substrate or a film formed on the etchingsubstrate and then applying an etching solution to the etching substratewhile rotating the etching substrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, applying ozone water in contact with aresist patterned on an etching substrate or a film formed on the etchingsubstrate and then applying an etching solution to the etchingsubstrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, applying ozone water in contact with aresist patterned on an etching substrate or a film formed on the etchingsubstrate and then applying an etching solution to the etching substratewhile rotating the etching substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, a substrate positioning unit having means forirradiating ultraviolet light to a substrate to be etched, a spinetching unit, and a robot arm for transferring the substrate from thesubstrate positioning unit to the spin etching unit.

Another invention disclosed in the specification is a solution applyingapparatus having, means for rotating a substrate and means for applyingan etching solution to a surface of one of the substrate and a film tobe formed on the substrate using a resist patterned on the surface whilerotating the substrate, wherein the etching solution is applied to anentire upper surface of the substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for rotating a substrate and means for applyingan etching solution to a surface of one of the substrate and a film tobe formed on the substrate using a resist patterned on the surface whilerotating the substrate, wherein the applying means has an etchingsolution outflow portion which moves over and in parallel to the surfacewhile applying the etching solution, and the etching solution outflowportion passes through a substantially rotation center portion of thesubstrate.

Another invention disclosed in the specification is a solution applyingapparatus having means for rotating a substrate and means for applyingan etching solution to a surface of one of the substrate and a film tobe formed on the substrate using a resist patterned on the surface whilerotating the substrate, wherein the applying means has an etchingsolution outflow portion which moves over and in parallel to the surfacewhile applying the etching solution, and the etching solution outflowportion passes through a substantially rotation center portion of thesubstrate and a moving trace of the etching solution outflow portion hasan arc shape.

Another invention disclosed in the specification is a solution applyingapparatus having, means for rotating a substrate, and means for applyingan etching solution to a surface of one of the substrate and a film tobe formed on the substrate using a resist patterned on the surface whilerotating the substrate, wherein the applying means simultaneouslyapplies to the etching solution in at least a range of from a rotationcenter portion of the substrate to an outermost portion.

Another invention disclosed in the specification is a solution applyingapparatus having means for applying a solution including a metal elementuniformly to a substrate on which a patterned resist is formed or a filmformed on the substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for irradiating ultraviolet light to a resistpatterned on a substrate or a film formed on the substrate and means forapplying a solution including a metal element to the substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for irradiating ultraviolet light to a resistpatterned on a substrate or a film formed on the substrate, means forapplying a solution including a metal element to the substrate, andmeans for rotating the substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for applying ozone water in contact with aresist patterned on a substrate or a film formed on the substrate andmeans for applying a solution including a metal element to thesubstrate.

Another invention disclosed in the specification is a solution applyingapparatus having, means for applying ozone water in contact with aresist patterned on a substrate or a film formed on the substrate, meansfor applying a solution including a metal element to the substrate, andmeans for rotating the substrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, irradiating ultraviolet light to a resistpatterned on a substrate or a film formed on the substrate and thenapplying a solution including a metal element to the substrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, irradiating ultraviolet light to a resistpatterned on a substrate or a film formed on the substrate and thenapplying a solution including a metal element to the substrate whilerotating the substrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, applying ozone water in contact with aresist patterned on a substrate or a film formed on the substrate andthen applying a solution including a metal element to the substrate.

Another invention disclosed in the specification is a solution applyingmethod having the steps of, applying ozone water in contact with aresist patterned on a substrate or a film formed on the substrate andthen applying a solution including a metal element to the substratewhile rotating the substrate.

Another invention disclosed in the specification is a solution applyingapparatus having, a substrate positioning unit having means forirradiating ultraviolet light to a substrate, a spin coating unit, and arobot arm for transferring the substrate from the substrate positioningunit to the spin coating unit.

Another invention disclosed in the specification is a solution applyingapparatus having, means for rotating a substrate and means for applyinga solution including a metal element to the substrate or a film to beformed on the substrate using a patterned resist while rotating thesubstrate, wherein the solution is applied to an entire upper surface ofthe substrate within a desired time.

Another invention disclosed in the specification is a solution applyingapparatus having, means for rotating a substrate and means for applyinga solution including a metal element to the substrate or a film to beformed on the substrate using a patterned resist while rotating thesubstrate, wherein the applying means has a solution outflow portionwhich moves over and in parallel to a surface of the substrate whileapplying the solution, and the solution outflow portion passes through asubstantially rotation center portion of the substrate.

Another invention disclosed in the specification is a solution applyingapparatus having means for rotating a substrate and means for applying asolution including a metal element to the substrate and a film to beformed on the substrate using a patterned resist while rotating thesubstrate, wherein the applying means has a solution outflow portionwhich moves over and in parallel to a surface of the substrate whileapplying the solution, and the solution outflow portion passes through asubstantially rotation center portion of the substrate and a movingtrace of the solution outflow portion has an arc shape.

Another invention disclosed in the specification is a solution applyingapparatus having, means for rotating a substrate, and means for applyinga solution including a metal element to the substrate and a film to beformed on the substrate using a patterned resist while rotating thesubstrate, wherein the applying means simultaneously applies to thesolution in at least a range of from a rotation center portion of thesubstrate to an outermost portion.

In general, the contact angle of an etching solution with respect to theresist is reduced by irradiating ultraviolet light to the hardenedresist for a desired period, or bringing it into contact with ozonewater (water in which ozone (O₃) has dissolved at 0.1 to 20 ppm), sothat a wetting degree of the etching solution is greatly increased.

The present invention makes use of this phenomenon, and before applyingthe solution, ultraviolet light is irradiated to the patterned andhardened resist which is formed on the substrate, or the resist isbrought in contact with ozone water. It is thus possible to performuniform etching without irregularities within a single substratesurface, even using an etching solution with a large contact angle, inan etching method in which the moving speed of the etching solution overthe surface to be etched is fast, for example, spin etching.

Further, even with fine patterns in which the pattern width is of theorder of several μm or less, since an etching solution penetratesadequately between the resists forming the pattern, uniform etching ispossible.

It is even possible to prevent the occurrence of etching irregularitieswhen the substrate is large.

The cause of the increased wetting of the applied etching solutionresulting from ultraviolet light irradiation or ozone water processingmay result from the following. That is, by ultraviolet light irradiationand ozone water contact to the hardened resist, an organic substance (oran organic contamination) on the surface of the resist is decomposed andremoved and simultaneously the surface of the resist is activated, sothat a surface energy of the resist decreases and a contact angle to asolution becomes small. Ultraviolet light irradiation is moreeffectively performed in an oxygen atmosphere since reactivity with anorganic substance is increased.

The result that the contact angle of a solution becomes small byultraviolet light irradiation or ozone water contact to the hardenedresist is exhibited temporarily, and after that, the contact angle onceagain increases after a desired time.

The time during which the contact angle is decreased varies depending onthe ultraviolet light irradiation time or the contact time with ozonewater, the intensity of the ultraviolet rays (ultraviolet light), andthe ozone concentration of the ozone water, but in air it is severalminutes to several hours. It is therefore desirable to perform theultraviolet light irradiation process or the ozone water contact processimmediately before applying a solution.

Further, in spin etching, as a method for uniformly etching, other thanirradiating the resist with ultraviolet light or bringing it intocontact with ozone water, there is an improved method in which anetching solution is applied within a desired period onto the uppersurface of an etching substrate having a resist or a resist on a film,in such a way that the etching solution drops or flows over the entireupper surface of the etching substrate which is rotating.

In comparison with a case wherein an etching solution is caused to dropor flow only near the center of the rotating surface of the substrate,in the above method, an etching solution is uniformly applied so thatetching is performed uniformly.

Specifically, the etching solution outflow port (tip) of the nozzlewhich causes an etching solution to drop or flow moves in a directionparallel to the surface of the substrate, so that the etching solutionis caused to drop or flow over the entire surface of the substrate.

Alternatively, an etching solution may be caused to flow or dropsimultaneously over at least a range from the center of rotation of anetching substrate to the periphery thereof in the form of a shower. Inother words, since an etching solution is caused to drop or flow (apply)onto the entire surface of the substrate, due to at least one rotationof the substrate, the etching solution is applied uniformly.

By adding an ultraviolet light irradiation process or a process in whichozone water is brought into contact, before the process in which theetching solution is applied, the etching solution is performed even moreuniformly.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A to 1F show the thin film transistor forming processes in anembodiment of the present invention;

FIG. 2 shows a spin etching apparatus;

FIG. 3 shows a single wafer processing system in which a spin etchingapparatus and other apparatus have integrated;

FIG. 4 shows another spin etching apparatus;

FIG. 5 is the upper view of the spin etching apparatus of FIG. 4;

FIG. 6 shows another spin etching apparatus;

FIG. 7 shows a spin coating apparatus; and

FIGS. 8A to 8C show crystallization processes of an amorphous siliconfilm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiment 1

In the embodiment, a process in which ultraviolet light is irradiated isperformed before the etching process in the manufacture of a Pchannel-type pixel thin film transistor (TFT) used in an active matrixtype liquid crystal electro-optical device. FIGS. 1A to 1F show theforming processes of the P-channel type pixel TFT in the embodiment.

In FIG. 1A, a silicon oxide film is formed to a thickness of 3000 Å bysputtering as a base film 102 on a glass substrate 101 (Corning #7059,100 mm×100 mm). An amorphous silicon film is then formed to a thicknessof 500 Å by plasma CVD, and then crystallization is performed by thethermal annealing in a nitrogen atmosphere for 12 hours at 600° C.Further, laser annealing is performed to improve crystallization. Theenergy density of the laser is suitably 250 to 350 mJ/cm², in theembodiment, 300 mJ/cm².

An island-like silicon film 103 is formed by patterning the crystallizedsilicon film. The silicon film 103 forms the active layer of the TFT. Asilicon oxide film is formed to a thickness of 1000 Å by sputtering as agate insulating film 104 to cover the island-like silicon film 103.

After this, an aluminum film with a thickness of 6000 Å is formed by lowpressure CVD. A photoresist (in this case OFPR-800 (30 cp) manufacturedby the Tokyo Ohka company) is applied to the upper surface of thealuminum film by spin coating. This is sub-sintered at 90° C., exposedto light, developed, main-sintered, and patterned, thereby forming ahardened photoresist 105.

The substrate 101 is then introduced into a chamber of a spin etchingapparatus chamber to perform ultraviolet light irradiation and etchingof the aluminum film, so that a gate electrode 106 is formed. It ispreferable to move the substrate 101 using a conveying unit such as arobot arm.

A description will be given relating to the spin etching apparatus inFIG. 2.

The substrate 101 is held onto a stage 201 by a vacuum chuck. The stage201 is connected to a motor (not shown), and is rotated by it.

An ultraviolet light irradiating source 200 is arranged into thechamber. The ultraviolet light source should irradiate light at awavelength of 400 nm or less. In this embodiment, a 365 mm high pressuremercury lamp is used.

The substrate 101 is introduced into the chamber, and then held onto thevacuum chuck. Further, ultraviolet light is irradiated into aphotoresist (mask) 105 from the ultraviolet light irradiating source200. The irradiation time is 5 to 180 seconds, in this case 60 seconds.The output is 3 mW/cm² on the substrate 101.

By the ultraviolet light irradiation, the contact angle of the etchingsolution with respect to the surface of the photoresist is changed fromapproximately 30° (prior to ultraviolet light irradiation after washingwith pure water) to approximately 4° (after ultraviolet lightirradiation), and thus the contact angle is greatly reduced. Thisrepresents by the fact that the surface energy of the surface of thephotoresist is reduced by the ultraviolet light irradiation. The contactangle of the etching solution with respect to the surface to be etchedis measured by placing the substrate at rest horizontally in a room witha constant temperature of 25° C., and dropping a single droplet of theetching solution onto the surface using a syringe.

Next, a first nozzle 203 is moved to the vicinity of the center of theupper surface of the substrate 101, and then allows an etching solutionto flow in the center portion while the substrate 101 is rotating. Anetching solution which is allowed to flow onto the substrate 101 ismoved toward the outside of the substrate 101 by the centrifugal forcedue to the rotation of the stage 201, and it flies off to the cap 202.The etching solution on the cap 202 collects in a waste solution tank(not shown) through a waste solution opening 205.

Here, 45° C. aluminum mixed acid (phosphoric acid+acetic acid+nitricacid) is caused to flow from the first nozzle 203 as the etchingsolution, and etching is performed for 4 minutes while the substrate 101is rotated at 500 rpm. The etching rate is 1500 Å/minute.

After etching, A second nozzle 204 is used to cause pure water to flowonto the center of the upper surface of the substrate 101 which isrotating, thereby cleaning the upper surface of the substrate 101.Before etching, the substrate may be cleaned by the same manner.

Also, after etching, a gate electrode 106 is formed. At this time,etching is performed uniformly in the surface of the substrate 101.(FIG. 1A).

When etching is performed under the same condition except for (without)ultraviolet light irradiation, a number of regions in which etching isnot performed sufficiently are present in an island form. In particular,a number of regions in which etching is not performed sufficiently arepresent in a peripheral (outside) portion.

When the etching process is completed, the substrate 101 is taken outfrom the spin etching apparatus, to anodize the gate electrode 106.

In FIG. 1B, a porous anodic oxide 107 is formed to a thickness of 0.1 to1 μm, in this case 0.5 μm, on the side surface of the gate electrode 106using a 3% sulfuric acid solution, without removing the photoresist(mask) 105. Also, after the photoresist 105 is removed, using anethylene glycol solution containing 3 to 10% of tartaric acid, boricacid and phosphoric acid, neutralized to a pH of approximately 7 withammonia, a fine anodic oxide 108 is formed to a thickness of 1500 Å onthe side surfaces and the upper surface of the gate electrode 106.

Boron is then implanted in the island-like silicon film 103 as animpurity by ion doping, using the gate electrode 106 and the anodicoxides 107 and 108 as masks, to form the active layer of thesemiconductor in a self-alignment. The dose is 1×10¹⁵ to 8×10¹⁵atoms/cm², and the acceleration voltage is 40 to 80 kV, for example, thedose is 5×10¹⁵ atoms/cm², and the acceleration voltage is 65 kV. As aresult, a P-type impurity region (source/drain regions) 109 and anintrinsic region 111 (channel region) with an offset region 110 in whichthe concentration of the P-type impurity is extremely low are formed. Itis possible to reduce the leak current by the offset region when thedevice is turned off. (FIG. 1B).

The porous anodic oxide is etched using a mixture of phosphoric acid,acetic acid and nitric acid. Only the porous anodic oxide 107 is etchedby this etching, and a fine anodic oxide 108 remains. The etching rateis approximately 600 Å/minute.

The impurity ions implanted in the active layer are activated byirradiating with a KrF excimer laser (wavelength of 248 nm, pulse widthof 20 nsec).

After this, a silicon nitride film is formed as an interlayer insulatingfilm 112 to a thickness of 3000 Å over the entire surface by plasma CVD.

In FIG. 1C, a photoresist (mask) which is patterned and sintered isformed on the upper surface of the interlayer insulating film 112. Usingthis mask, the interlayer insulating film 112 is etched, the gateinsulating film 105 and the anodic oxide 107, to form contact holes 113and 114.

Ultraviolet light irradiation is performed on the photoresist (mask) inthe same way as in the forming process of the gate electrode 106, toincrease a wetting degree of the photoresist (mask). After that, thesubstrate is moved to the spin etching apparatus of FIG. 2, to performspin etching.

Etching is performed on the interlayer insulating film 112 includingsilicon nitride, and the gate insulating film 104 including siliconoxide. Here, buffered hydro-fluoric acid (BHF) (NH₄ F:HF=10:1) is causedto flow from the first nozzle 203 as an etching solution, and etching isperformed for 4 minutes with the substrate 101 rotating at 500 rpm. Theetching rate is approximately 1000 Å/minute.

After etching, while the substrate 101 is rotated, it is washed withpure water applied from the second nozzle 204.

Further, the substrate is moved to a chamber of another apparatus havingthe same construction as that in FIG. 2, to etch the fine anodic oxide108. If necessary, it is also possible to perform ultraviolet lightirradiation to the photoresist (mask) before etching.

Here, an aqueous mixture of 3% phosphoric acid plus 3% anhydrous chromicacid, heated to 70°, is used as the etching solution, and etching isperformed for 4 minutes with the substrate rotating at 500 rpm. Theetching rate is 40 Å/minute. After etching, the substrate is washed withpure water. In this way, contact holes 113 and 114 are formed in thesource region and the gate electrode region through two etchingprocesses (FIG. 1C).

Further, an aluminum film is formed to a thickness of 6000 Å bysputtering, and in the same way as the process whereby the gateelectrode 106 is formed, the photoresist (mask) is subjected toultraviolet light irradiation. After this, spin etching for the aluminumfilm is performed to form a source electrode 115 and a gate electrode116. The conditions in this case are the same as for the etching of thegate electrode 106 (FIG. 1D).

A silicon oxide film is then formed to a thickness of 2000 Å by plasmaCVD as a passivation film 117. A resist is applied onto the passivationfilm 117, patterned and sintered, to form an etching mask. Using thismask, etching is performed on the passivation film 117, the interlayerinsulating film 112 and the gate insulating film 104. Bufferedhydrofluoric acid (BHF) (NH₄ F:HF=10:1) is used as the etching solution,and spin etching is performed after ultraviolet light irradiation. Theetching time is 6 minutes, the etching rate is approximately 1000Å/minute and the speed of rotation is 500 rpm. A washing process is thenperformed in the same way. In this way, a contact hole 118 is formed.(FIG. 1E).

Further, ITO film is formed to a thickness of 800 Å by sputtering andthen a photoresist (mask) is formed. Further, ultraviolet lightirradiation is performed in the same way, and then spin etching isperformed. The etching solution is ITO mixed acid (HCl:H₂ O:HNO₃=1:1:0.03). The etching time is 0.5 minutes, the etching rate is 1600Å/minute and the speed of rotation is 500 rpm. A washing process is thenperformed in the same way. By etching in this way, a contact hole isformed, a pixel electrode 119 is formed and a pixel TFT is thusproduced. No etching irregularities appear in any of the etchingprocesses. (FIG. 1F)

An ultraviolet light irradiation process to a photoresist (mask) may beadded before the pure water washing process in the embodiment. In thisway, since wetting degree of the photoresist (mask) is increased, it ispossible to perform pure water washing more effectively. Also, it isalso possible to provide an ultraviolet light source such as a highpressure mercury lamp within the chamber of the spin etching apparatusof FIG. 2, and to perform etching and ultraviolet light irradiationwithin the same chamber. Further, by increasing the number of nozzles,it is possible to cause a plurality of etching solutions to flow from aplurality of nozzles, and it is therefore possible to perform differenttypes of etching continuously within the same chamber.

Embodiment 2

The embodiment is an example of a spin etching system in which a spinetching apparatus and other apparatuses are provided integrally, asshown in FIG. 3. A robot arm 302 for moving the substrate 101 isprovided at the center on a main body 301. A cassette 303 which houses aplurality of substrates 101, a substrate positioning (alignment) unit304 and a spin etching apparatus 305 are provided such that theysurround the robot arm 302. An ultraviolet light irradiating unit 304asuch as a high pressure mercury lamp which irradiates ultraviolet lightfrom the top is provided in the positioning unit 304, and thereforeultraviolet light can be irradiated at the same time as positioning iseffected, and therefore the process is simplified.

In FIG. 3, a first nozzle which causes an etching solution to flow, anda second nozzle which causes pure water to flow for washing are providedin the spin etching apparatus 305, and thus washing, etching and drying(spin drying) can be performed within the same chamber.

Further, a washing chamber and chambers for performing different typesof etching may be provided on the main body, and treatment performed ineach chamber.

Embodiment 3

The embodiment is an example of processes in which ozone water isbrought into contact with the resist prior to the etching process, andin which a P channel-type pixel TFT, as used in an active matrix typeliquid crystal electro-optical device, is formed. The manufacturingprocess for the P-channel type pixel TFT of the embodiment is shown inFIGS. 1A to 1F.

In FIG. 1A, a silicon oxide film is formed to a thickness of 3000 Å bysputtering as a base film 102 on a glass substrate 101 (Corning #7059,100 mm×100 mm). An amorphous silicon film is then formed to a thicknessof 500 Å by plasma CVD, and then which crystallization is performed bythe thermal annealing in a nitrogen atmosphere for 12 hours at 600° C.Further, laser annealing is performed to improve crystallization. Theenergy density of the laser is suitably 250 to 350 mJ/cm², in theembodiment 300 mJ/cm².

An island-like silicon film 103 is formed by patterning the crystallinesilicon film formed in this way. The island-like silicon film 103 formsthe active layer of the TFT. A silicon oxide film is formed to athickness of 1000 Å by sputtering as a gate insulating film 104 to coverthe island-like silicon film 103.

After this, an aluminum film with a thickness of 6000 Å is formed by lowpressure CVD. A photoresist (in this case OFPR-800 (30 cp) manufacturedby the Tokyo Ohka company) is applied to the upper surface of thealuminum film by spin coating, sub-sintered at 90° C., exposed to light,developed, main-sintered, and patterned, to form a photoresist (mask)105. Using the photoresist 105, the aluminum film is etched to form agate electrode 106. (FIG. 1A)

In order to form the gate electrode 106, the substrate 101 is thenintroduced into a chamber provided with an ultraviolet light source, andthen the photoresist 105 is irradiated with ultraviolet light for 5 to180 seconds, in this case 60 seconds. The ultraviolet light sourceshould irradiate light at a wavelength of 400 nm or less, and in thiscase a 365 mm high pressure mercury lamp is used. The output is 3 mW/cm²on the substrate 101.

Immediately after the ultraviolet light irradiation, the substrate 101is introduced into the spin etching system in FIG. 7. It is preferableto move the substrate 101 using a conveying unit such as a robot arm.

The substrate 101 is held on a stage 601 by a vacuum chuck. The stage601 is connected to a motor (not shown) and rotated.

While the substrate 101 is rotating, the first nozzle 203 is moved closeto the center on the surface of the substrate 101, and causes ozonewater to flow toward the center of the upper surface of the substrate101. A solution into which 0.1 to 20 ppm concentration of ozone isdissolved can be used as the ozone water, and here a solution in which 2ppm of ozone is dissolved is used.

Ozone water applied on the substrate 101 is moved from an outside of thesubstrate 101 by centrifugal force due to rotation of the stage 601, sothat it flies off to the cap 202. The etching solution on the cap 202collects in a waste solution tank (not shown) through a waste solutionopening 606.

While the ozone water is allowed to flow from the first nozzle 603, thesubstrate 101 is rotated for 3 minutes at a speed of rotation of 3000rpm, and ozone water comes into contact with the entire surface of thesubstrate 101. The speed of rotation is then set to 2500 rpm, and theozone water on the substrate 101 is dried by spin dry.

The second nozzle 604 is moved to the center of the upper surface of thesubstrate, and causes etching solution to flow in the center of theupper surface of the substrate 101. Aluminum mixed acid (phosphoricacid+acetic acid+nitric acid) at 45° C. is used. Etching is performedwhile the substrate 101 is rotated for 4 minutes at a speed of 500 rpm.The etching rate is 1500 Å/minute.

After etching, a third nozzle 605 is moved to the center portion ofrotation of the substrate 101 to cause pure water to flow.

The contact angle of the etching solution with respect to thephotoresist surface is changed from approximately 30° (before the ozonewater has flowed and after washing with pure water) into approximately7° (after the ozone water has flowed), and thus the contact angle isgreatly reduced by the contact with the ozone water. This represents bythe fact that the surface energy of the photoresist surface is reducedby the contact of the ozone water with the resist surface. The contactangle with respect to the substrate surface is measured by accuratelyplacing the substrate horizontally within a chamber at a constanttemperature of 25° C., and dropping a single droplet of ozone water ontothe substrate using a syringe.

After the etching process in this way, a gate electrode 106 is formed.At this time, etching is performed uniformly within the substratesurface. (FIG. 1A)

However, if etching is performed under the same conditions, except thatthe ozone water flow process is not performed, a large number ofisland-like regions exist in which etching is insufficient. Inparticular, there are a large number of regions at the periphery inwhich etching is etching is insufficient.

A porous anodic oxide 107 is then formed to a thickness of 0.1 to 1 μm,here 0.5 μm, on the side surfaces of the gate electrode 106 using a 3%sulfuric acid solution, without removing the photoresist (mask) 105. Thephotoresist 105 is then removed, and using an ethylene glycol solutioncontaining 3 to 10% of tartaric acid, boric acid and phosphoric acid,which has neutralized to a pH of approximately 7 using ammonia, a fineanodic oxide 108 is formed to a thickness of 150Å on the upper surfaceand side surfaces of the gate electrode 106.

Boron is then implanted in a self-alignment as an impurity into theisland-like silicon film 103 by ion doping, with the gate electrode 106and the anodic oxides 107 and 108 as masks. The dose is 1×10¹⁵ to 8×10¹⁵atom/cm², and the acceleration voltage is 40 to 80 kV, for example thedose is 5×10¹⁵ atoms/cm², and the acceleration voltage is 65 kV. As aresult, a P-type impurity region (source/drain regions) 109, and anintrinsic region 111 (channel region) with an offset region 110 in whichthe concentration of the P-type impurities is extremely low are formed.It is possible to reduce the leak current when the device is turned off,by the offset regions 110. (FIG. 1B).

After this, the porous anodic oxide 107 is etched using a mixture ofphosphoric acid, acetic acid and nitric acid. Here, only the porousanodic oxide 107 is etched and the fine anodic oxide 108 remains. Theetching rate is approximately 600 Å/minute.

Further, a KrF excimer laser (wavelength of 248 nm, pulse width of 20nsec) is irradiated to activate the impurity ions introduced into theactive layer.

After this, a silicon nitride film is formed to a thickness of 3000 Å byplasma CVD as an interlayer insulating film 112, over the entiresurface.

A photoresist is patterned on the upper surface of the layer insulatingfilm 112 and sintered, and then the interlayer insulating film 112, thegate insulating film 105 and the anodic oxide 107 are etched to formcontact holes 113 and 114.

In order to form the contact holes 113 and 114, after the substrate isplaced into the apparatus of FIG. 6 and ozone water is in contact withthe resist, spin etching is performed.

Etching is performed to form contact holes in the interlayer insulatingfilm 112 comprising silicon nitride, and the gate insulating film 105comprising silicon oxide.

Ozone water is caused to flow from the first nozzle 603 in the same wayas in the forming process of the gate electrode 106 and to be in contactwith the photoresist (mask). Then, buffered hydrofluoric acid (BHF) (NH₄F:HF=10:1) is caused to flow from the second nozzle 604 as an etchingsolution, and etching is performed for 4 minutes with the substraterotating at 500 rpm. The etching rate is 1000 Å/minute.

After etching, while rotating the substrate 101, pure water is caused toflow from the third nozzle 605, to wash the substrate 101. Also, thesubstrate 101 is moved to a chamber of another apparatus having the sameconstruction as that in FIG. 6, and then the anodic oxide 108 is etched.Before this etching, ozone water may be in contact with the photoresistagain. An aqueous mixture of 3% phosphoric acid plus 3% anhydrouschromic acid which has heated to 70° is used as the etching solution,and etching is performed for 4 minutes with the substrate rotating at500 rpm. The etching rate is 400 Å/minute.

After etching, while rotating the substrate 101, washing is performedusing pure water applied from the third nozzle 605. In this way contactholes 113 and 114 are formed in the source region and the gate region.(FIG. 1C)

In the embodiment, etching of the interlayer insulating film 112 and thegate insulating film 105 and etching of the anodic oxide 108 areperformed in different etching apparatuses, respectively. However, Byarranging a further nozzle in the etching apparatus of FIG. 6 and thenapplying different etching solutions, two etching processes may beperformed in the same etching process.

An aluminum film is formed to a thickness of 6000 Å by sputtering, and asource electrode 115 and a gate electrode 116 are formed by ozone waterflow and spin etching on the patterned photoresist in the same way aswith the gate electrode outlined above. The conditions are the same asfor the etching of the gate electrode 106 outlined above. (FIG. 1D)

After this, a silicon oxide film is formed to a thickness of 2000 Å byplasma CVD as a passivation film 117.

A resist is applied, patterned, sintered, and formed on the passivationfilm 117, and etching is performed on the passivation film 117, theinterlayer insulating film 112 and the gate insulating film 104.Buffered hydrofluoric acid (BHF) (NH₄ F:HF=10:1) is used as the etchingsolution, and after ozone water flow, spin etching is performed. Theetching time is 6 minutes, the etching rate is 1000 Å/minute, and therotation speed is 500 rpm. The washing process is then performed in thesame way. In this way a contact hole 118 is formed. (FIG. 1E)

Further, an ITO film is formed to a thickness of 800 Å by sputtering,and after forming a photoresist, ozone water flow is performed in thesame way, and spin etching is performed. The etching solution is ITOmixed acid (HCl:H₂ O:HNO₃)=1:1:0.03. The etching time is 0.5 minutes,the etching rate is 1600 Å/minute, and the rotation speed is 500 rpm.The washing process is then performed in the same way.

In this way, a pixel electrode 119 is formed by etching, and a pixel TFTis manufactured. No etching irregularities were seen in any of theetching processes. (FIG. 1F)

In the embodiment, it is also possible to add an ozone water flowprocess before the washing process using pure water. In this way, it ispossible to perform washing by pure water more effectively.

In the embodiment, ozone water flow and spin etching may be performed inindividual chambers, and they may be performed while the substrate isrotated. In the ozone water flow process, the substrate may not berotated.

The method whereby wetting degree of the resist surface is improved bycausing ozone water to flow can be achieved simply by increasing thenumber of nozzles in a conventional spin etching apparatus, or byaltering the type of solution which is caused to flow, and therefore nonovel design of apparatus or the like is required.

The ultraviolet light irradiation in the first embodiment and the ozonewater flow of the present embodiment may also be combined.

By increasing the number of nozzles, it is possible to cause etchingsolution to flow from a plurality of nozzles, and it is thereforepossible to perform different types of etching continuously within thesame chamber.

Also, in FIG. 3, a first nozzle for applying ozone water, a secondnozzle for applying an etching solution, a third nozzle for applyingpure water for washing are arranged in the spin etching apparatus 305,and then in the same chamber, washing, ozone water applying, etching anddry (spin dry) are performed. In this state, the ultraviolet lightirradiating source 304a of the positioning unit 304 may be not arranged.

A chamber for ozone water applying, a chamber for washing, a chamber fordifferent types of etching and the like may be arranged in the main body301, to perform processing in each chamber.

Embodiment 4

FIG. 4 shows the spin etching apparatus of the embodiment, and FIG. 5 isa top view of FIG. 4. In Embodiment 4, as in Embodiments 1 to 3, theconstruction is not one in which etching solution is dropped or causedto flow only near the center of the substrate to be etched, butindicates construction in which etching solution is caused to drop andflow over the entire upper surface (rotating surface) of the substrateto be etched, which is rotated, within a desired period. The spinetching apparatus in FIGS. 4 and 5 is the same construction as that inFIG. 2, except for the nozzle for applying an etching solution.

In Embodiment 4, the spin etching apparatus of FIG. 4 is used, and asshown in FIG. 1A, a substrate 101 which is to be etched and on which apatterned hardened photoresist has been formed, is introduced into thespin etching apparatus and then etching is performed, as in Embodiment1.

In FIG. 4, the substrate 101 is held to a stage 201 by a vacuum chuck.The stage 201 is connected to a motor, which is not shown, and isrotated. Etching solution 410 is caused to flow from above the rotatingsubstrate by a nozzle 401.

In FIG. 5, the nozzle 401 which extends from the rotating surface of thesubstrate 101 oscillates to the left and right in a direction parallelto the surface of the substrate 101 while the etching solution outflowportion (in other words, the tip) 401a passes approximately through thecenter of the rotating surface of the substrate 101.

The nozzle 401 oscillates such that the locus (trace) of movement of theetching solution outflow portion 401a has an arc shape and passedthrough the center of rotation of the substrate 101, but it is alsopossible to attach the nozzle 401 to a linear motor or the like, and tooscillate such that its trace has a straight line.

In FIG. 5, when the nozzle 401 oscillates such that the locus of theoutflow portion 401a has an arc shape, it is possible to move theoutflow portion 401a of the nozzle 401 parallel to the rotating surfaceof the substrate 101 by an extremely simple construction.

Arrangements are made such that the nozzle 401 moves from one side ofthe periphery of the rotating surface to the other side in 0.5 toseveral seconds, depending on the surface area of the substrate 101, inorder to cause etching solution to drop or flow onto the entire uppersurface of the substrate 101. The range of movement of the nozzle 401may be between the position indicated by the solid line passing throughthe center of the rotating substrate 101 and either of the positionsshown by the dotted lines (for example on the right).

Using the spin etching apparatus in FIG. 4, the aluminum film formed onthe substrate 101 is etched. 45° C. aluminum mixed acid (phosphoric acidplus acetic acid plus nitric acid) is caused to flow from the nozzle 401as the etching solution, and etching is performed for 4 minutes with thesubstrate rotating at 500 rpm. The etching rate is 1500 Å/minute.

As a result, etching is performed uniformly within the surface of thesubstrate 101, and no regions of insufficient etching are seen.

Thus, in FIG. 4, even if an area of the substrate 101 is increased, itis possible to perform etching uniformly within the surface of thesubstrate, since, in comparison with a case in which etching solution iscaused to drop or flow only at the center of the rotating surface of thesubstrate, etching solution is applied uniformly onto the substrate.

Embodiment 5

FIG. 6 shows another construction of the spin etching apparatus of theembodiment.

A linear etching outflow nozzle 601 is provided parallel to and abovethe rotating surface of the substrate 101. By a plurality of holes 502provided in the nozzle 501, etching solution 610 is caused to drop andflow simultaneously onto the surface of the substrate 101, and isapplied onto the substrate 101.

The width over which etching solution is caused to drop and flow by thenozzle 501 must be at least half of the length of the diagonal acrossthe substrate. In this case, etching solution is applied uniformly overthe entire upper surface of the substrate by one rotation of thesubstrate.

In FIG. 6, the nozzle 501 causes etching solution to drop and flow overthe entire length of the diagonal across the substrate. Thus etchingsolution is applied uniformly over the entire upper surface of thesubstrate 101 by half a rotation of the substrate 101.

Even if spin etching is performed while etching solution is caused toflow in the form of a shower, it is possible to apply etching solutionuniformly onto the upper surface of the substrate in the same way as theapparatus of FIG. 4. As a result, it is possible to perform uniformetching within the surface of the substrate.

When, before etching process, ultraviolet light irradiation or ozonewater contact to the surface of a photoresist is performed, it iseffective perform uniform etching within the surface of the substrate.

Embodiment 6

In the embodiment, a desired mask pattern is formed on the surface of anamorphous silicon film using a resist mask, and then a metal elementsuch as nickel is introduced selectively into the amorphous silicon filmby applying a solution containing the nickel from above the maskpattern.

FIGS. 8A to 8C show forming processes in the embodiment. An amorphoussilicon film 702 having a thickness of 500 Å is formed on a glasssubstrate 701 (Corning #7059, 10 cm×10 cm) by plasma CVD. A resist isformed on the surface of the film 702. The resist may be a positive ornegative type. By commonly used photolithography patterning process, aresist mask 703 is patterned to a desired pattern. (FIG. 8A)

In this state, ultraviolet light is irradiated into the resist mask 703.In the embodiment, the ultraviolet light source is 365 nm high pressuremercury lamp. The output is set to 3 mW/cm² on the surface of thesubstrate 701. The irradiation time is set to about 5 to 180 seconds.

An acetate solution (5 ml) containing nickel of 100 ppm is applied in acase wherein the substrate has 10 cm×10 cm in size by using theapparatuses of FIGS. 4 to 6 as a spin coater.

While a stage 201 is rotated at a rotation speed of 50 rpm, a nickelacetate solution is applied (dropped) from a nozzle 401 (501), toperform spin coating for 10 seconds. Since ultraviolet light hasirradiated into the resist mask 703 and therefore a contact angle to asolution becomes small, a film 704 is formed uniformly on the entiresurface of the substrate 701.

After this state is maintained for 5 minutes, the stage 201 is rotatedat a rotation speed of 2000 rpm, to performing spin dry. This state maybe maintained while the stage 201 is rotated at a rotation speed of 0 to150 rpm. (FIG. 8B)

When the resist mask 703 is removed by oxygen ashing, in an openingportion 703a, a region 705 which nickel element is adsorbed is formedselectively in the amorphous silicon film 702. The resist mask may beremoved by annealing in an atmosphere including oxygen.

After that, the amorphous silicon film 702 is crystallized by heatingtreatment at 550° C. for 4 hours in an atmosphere including nitrogen. Inthe state, as shown in an arrow in FIG. 8C, crystal growth is performedfrom the region 705 into which nickel is introduced to a region intowhich nickel is not introduced, along a transverse direction. In FIG.8C, numeral 706 represents a region into which nickel is introduceddirectly and which is crystallized, and numeral 707 is a region which iscrystallized in a transverse direction.

After crystallization process by heating treatment, it is useful toperform annealing by irradiation of laser light or intense light. Bythis, crystallinity of a crystalline silicon film is further increased.KrF excimer laser and XeCl laser may be used as laser light. It iseffective to use infrared light as intense light. Since infrared lightis not absorbed easily by a glass substrate and absorbed selectively bysilicon, large effect by annealing can be obtained.

Embodiment 7

In the embodiment, a desired mask pattern is formed on the surface of anamorphous silicon film using a resist mask, and then a metal elementsuch as nickel is introduced selectively into the amorphous silicon filmby applying a solution containing the nickel from above the maskpattern.

FIGS. 8A to 8C show forming processes in the embodiment. An amorphoussilicon film 702 having a thickness of 500 Å is formed on a glasssubstrate 701 (Corning #7059, 10 cm×10 cm) by plasma CVD. A resist isformed on the surface of the film 702. The resist may be a positive ornegative type. By commonly used photolithography patterning process, aresist mask 703 is patterned to a desired pattern. (FIG. 8A)

In this state, ozone water is applied in contact with the resist mask703. The apparatuses of FIGS. 4 to 6 may be used as a spin coater. Whilethe stage 201 is rotated at a rotation speed of 3000 rpm for 3 minutes,ozone water is applied (dropped) from the nozzle 401 (501). A solutionwhich ozone of about 1 to 20 ppm is dissolved into pure water may beused as ozone water.

An acetate solution (5 ml) containing nickel of 100 ppm is applied in acase wherein the substrate has 10 cm×10 cm in size by using theapparatuses of FIGS. 4 to 6 as a spin coater.

While a stage 201 is rotated at a rotation speed of 50 rpm, a nickelacetate solution is applied (dropped) from a nozzle 401 (501), toperform spin coating for 10 seconds. Since ozone water is applied incontact with the resist mask 703 and therefore a contact angle to asolution becomes small, a film 704 is formed uniformly on the entiresurface of the substrate 701.

After this state is maintained for 5 minutes, the stage 201 is rotatedat a rotation speed of 2000 rpm, to performing spin dry. This state maybe maintained while the stage 201 is rotated at a rotation speed of 0 to150 rpm. (FIG. 8B)

When the resist mask 703 is removed by oxygen ashing, in an openingportion 703a, a region 705 which nickel element is adsorbed is formedselectively in the amorphous silicon film 702. The resist mask may beremoved by annealing in an atmosphere including oxygen.

After that, the amorphous silicon film 702 is crystallized by heattreatment at 550° C. for 4 hours in an atmosphere including nitrogen. Inthis state, as shown by an arrow in FIG. 8C, crystal growth is performedfrom the region 705 into which nickel is introduced to a region intowhich nickel is not introduced, along a transverse direction. In FIG.8C, numeral 706 represents a region into which nickel is introduceddirectly and which is crystallized, and numeral 707 is a region which iscrystallized in a transverse direction.

In the embodiment, using the apparatus of FIG. 2, for example, ozonewater contact and nickel acetate solution applying can be performed inthe same apparatus. In this case, ozone water may be applied from thenozzle 203 and nickel acetate solution may be applied from the nozzle204.

In Embodiments 6 and 7, nickel is used as a metal element for promotingcrystallization of silicon. At least one element selected from Ni, Pd,Pt, Cu, Ag, Au, In, Sn, P, As, and Sb can be used.

By the present invention, it is possible to uniformly apply a solutionto a substrate on which a resist is formed by ultraviolet lightirradiation or ozone water contact to the surface of the resist because,to decrease a contact angle of the solution, in solution applyingmethods in which the moving speed of etching solution over the surfaceof the substrate is high, for example spin coating.

In particular, even when using a solution having a large contact angle,or even when fine patterns in which the pattern width is of the order ofseveral μm or less, a solution can penetrate sufficiently between theresists forming the pattern, so that uniform etching withoutirregularities and uniform crystallization of a silicon film ispossible.

Also, by suitably moving a solution outflow portion, it is possible toapply uniformly a solution in comparison with a conventional spincoating. Even if a substrate having large size is used, a solution canbe applied uniformly.

What is claimed is:
 1. An etching method for manufacturing asemiconductor device comprising the steps of:preparing a substratehaving a surface to be patterned; forming a resist mask on said surface;applying a liquid etchant to said surface having the resist maskthereon; selectively etching said surface by using said liquid etchantin accordance with said resist mask, wherein a wettability of a surfaceof said resist mask with respect to the liquid etchant is increased bytreating the surface of the resist mask before said applying step andwherein the wettability is increased by exposing the surface of theresist mask with water comprising ozone dissolved in a concentrationfrom 0.1 to 20 ppm.
 2. An etching method for manufacturing asemiconductor device comprising the steps of:forming a conductive filmover a substrate; forming a resist mask on said conductive film;treating a surface of said resist mask with a water comprising ozonedissolved in a concentration from 0.1 to 20 ppm; and then applying aliquid etchant to the conductive film having the resist mask thereonafter finishing the treatment with said water; and selectively etchingthe conductive film by using a liquid etchant in accordance with saidresist mask, wherein a wettability of a surface of said resist mask withrespect to the liquid etchant is increased by said water.
 3. An etchingmethod according to claim 2 wherein said conductive film comprisesaluminum.
 4. An etching method according to claim 2 wherein said liquidetchant comprises phosphoric acid, acetic acid and nitric acid.
 5. Amethod of manufacturing semiconductor device comprising the stepsof:depositing a semiconductor film comprising amorphous silicon on aninsulating surface of a substrate; crystallizing said semiconductorfilm; patterning the crystallizing semiconductor film into a pluralityof semiconductor islands; forming an insulating film over said pluralityof semiconductor islands; forming a conductive film on said insulatingfilm; forming a patterned mask on said conductive film; treating saidpatterned mask with water comprising ozone dissolved in a concentrationfrom 0.1 to 20 ppm; and then etching said conductive film into gateelectrodes in accordance with said patterned mask using a liquidetchant.
 6. A method according to claim 5 wherein said conductive filmcomprises aluminum.
 7. A method according to claim 5 wherein saidpatterned mask comprises a resist material.
 8. A method of manufacturinga semiconductor device comprising the steps of:depositing asemiconductor film comprising amorphous silicon on an insulating surfaceof a substrate; forming a patterned resist mask on said semiconductorfilm; treating said patterned resist mask and an exposed surface of saidsemiconductor film with water comprising ozone dissolved in aconcentration from 0.1 to 20 ppm to oxidize said exposed surface of saidsemiconductor film; and introducing a metal containing material forfacilitating crystallization of said semiconductor film after thetreating step.
 9. The method of claim 8 wherein said metal is selectedfrom the group consisting of Ni, Pd, Pt, Cu, Ag, Au, In, Sn, P, As, andSb.
 10. The method of claim 8 wherein a heat treating step is performedin order to crystallize said semiconductor film after introducing saidmetal containing material.
 11. The method of claim 10 wherein saidpatterned resist mask is removed before said heat treating step.